OK so what exactly is your concern? That a ‘non-state actor’ will employ some type of drone? It’s a possibility I suppose but from the POV of a terrorist I think a drone has some issues. If its a homemade drone, it’s unlikely to be able to be easily controlled or carry a serious weapon. If its not then the terrorist will need technical expertise and probably some type of tacit support from a state actor (note, for example, terrorists have yet to use a MiG fighter or attack helicopter).